[Qgis-developer] show grid on map canvas (similiar to grid used in composer) - strategy?

Etienne Tourigny etourigny.dev at gmail.com
Thu May 10 15:40:11 PDT 2012

Hi all

On Thu, May 10, 2012 at 5:39 PM, Martin Dobias <wonder.sk at gmail.com> wrote:
> Hi
> On Thu, May 10, 2012 at 2:06 PM, Nathan Woodrow <madmanwoo at gmail.com> wrote:
>> I think if QgsPluginLayer is a usable option that would be the way to go, or
>> maybe  QgsVectorLayer  but I suspect that you will need a provider for
>> that.
> I would suggest _not_ to create another provider for grids (for use as
> a vector layer). A grid is not really made of vector features, and
> lots of vector operations do not make much sense for grid. An
> interesting approach might be to use QgsPluginLayer class, but IMHO a
> grid is not even a layer... e.g. does it make any sense to draw some
> other layers on top of a grid?

I guess it makes more sense to draw the grid on top - are there any
uses to draw the grid below the layers? In any case, a simple
(top/bottom) selector would suffice.

> For me a grid is a good candidate to be implemented as another type of
> decoration (currently there is north arrow, scale bar and copyright
> label). A decoration is drawn on top of the map when map rendering has
> finished. And symbology can still be applied when drawing grid as a
> decoration.

Hmm... symbology applied to what?

Nathan's suggestion to make it a layer to be able to style it makes
sense. Any way we can use the symbology interface on a map decoration?
Can we re-use existing widgets for this, or just a waste or time
instead of designing a new widget?

> Regards
> Martin

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